#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<cmath>
#include<map>
#include<set>
#include<cstdio>
#include<algorithm>
#define debug(a) cout<<#a<<"="<<a<<endl;
using namespace std;
const int maxn=1e5+100;
typedef long long LL;
inline LL read(){LL x=0,f=1;char ch=getchar();	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
return x*f;}
int main(void)
{
  cin.tie(0);std::ios::sync_with_stdio(false);
  LL n,m;cin>>n>>m;
  LL sum=0;
  vector<pair<LL,LL>>v;
  bool flag=1;
  for(LL i=1;flag==1&&i<=n;i++){
    for(LL j=i+1;flag==1&&j<=n;j++){
        if(__gcd(i,j)==1){
            v.push_back({i,j});
            sum++;
        }
        if(sum>=m){
            flag=0;
            break;
        }
    }
  }
  if(flag==1||sum<n-1){
     cout<<"Impossible"<<"\n";
  }
  else{
     cout<<"Possible"<<"\n";
     for(auto i:v){
        cout<<i.first<<" "<<i.second<<"\n";
     }
  }
return 0;
}
